Which statement accurately describes a difference between DNA and RNA?

• A. RNA is double-stranded and contains deoxyribose sugar.
• B. RNA is single-stranded and contains ribose sugar; DNA is double-stranded and contains deoxyribose sugar.
• C. DNA is single-stranded and contains ribose sugar.
• D. Both are double-stranded with ribose sugar.

Answer: (B)

DNA and RNA differ in two main ways: their structure and the sugar in their backbone. DNA typically exists as a stable double-stranded molecule, built with deoxyribose sugar. RNA is usually single-stranded and uses ribose sugar, which has a hydroxyl group at the 2' position. This combination—single strand with ribose vs. double strand with deoxyribose—best fits the statement. The extra 2' hydroxyl on ribose makes RNA more chemically reactive and less stable, while the lack of it in deoxyribose helps DNA remain durable for long-term genetic storage. So the described contrast—RNA being single-stranded with ribose and DNA being double-stranded with deoxyribose—captures the key difference.